1) What airline are you considering? If you book SWA you can request a credit if the prices drop, only good if you will actually be using it within a year of booking for additional flights. AT also will issue credits good for luggage/seat assignments unlike SWA...however, this policy could change with pending merger.
2) What day of the week are you traveling? mid-week flights usually turn out to be a great deal down the road (i.e. a few months out) if you can take advantage of them
3) It's midweek

odd to see fares take big jump overnight (but standard on the weekends) Whatever airline/flight you're monitoring, are you able to see the available seats? A group may have booked the plane resulting in less seats open/higher prices for the remaining ones.
I've always booked ASAP, but have advised my DD to sit it out for her airfare needed the week after Thanksgiving this year. She'll monitor them for a sale but currently her flights are almost 70% more than her trip last year.
I've found that my flights are averaging 30% more than the same time frame last year

if that helps any. Good luck